1. Field
The following description relates to a communication method of a mobile terminal, a pico base station, and a macro base station in a heterogeneous network.
2. Description of Related Art
When a mobile terminal in a heterogeneous network is located within cell coverage of a plurality of base stations, it is important to determine which of the base stations can efficiently serve the mobile terminal, and the determination is typically made based on two criteria.
Ideally, the mobile terminal selects a base station that transmits the strongest signal, and that also has the least path loss between the mobile terminal and the base station.
Generally, in a communication system having a regular arrangement of hexagonal cells, each base station transmits a preamble signal with the same transmission power. However, in a heterogeneous network communication system including a base station of a macrocell providing a communication service for a wide area, a base station of a picocell providing a communication service for a hotspot area, and a base station of a femtocell providing a communication service for an office or a residence, each base station transmits a preamble signal with an appropriate transmission power for each type of cell. For example, the transmission power of the preamble signal transmitted by the base station of the macrocell may be higher than the transmission power of the preamble signal transmitted by the base station of the picocell, which in turn may be higher than the transmission power of the preamble signal transmitted by the base station of the femtocell.
When a cell is selected by comparing strengths of signals with different transmission powers received by a mobile terminal, there is possibility that different cells may be selected by the mobile terminal depending on positional relations between base stations even though the environments between the mobile terminal and the base stations are the same.